Photosensitive compositions, preparation methods thereof, quantum dot polymer composite prepared therefrom

ABSTRACT

A photosensitive composition including a quantum dot dispersion, a photopolymerizable monomer having a carbon-carbon double bond, and a photoinitiator, wherein the quantum dot dispersion includes an acid group-containing polymer and a plurality of quantum dots dispersed in the acid group-containing polymer, and wherein the acid group-containing polymer includes a copolymer of a monomer combination including a first monomer having a carboxylic acid group or a phosphonic acid group and a carbon-carbon double bond and a second monomer having a carbon-carbon double bond and a hydrophobic group and not having a carboxylic acid group and a phosphonic acid group.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2015-0119128 filed in the Korean Intellectual Property Office on Aug.24, 2015, and all the benefits accruing therefrom under 35 U.S.C. § 119,the content of which is incorporated herein in its entirety byreference.

BACKGROUND

1. Field

A photosensitive composition, a method of preparing the same, a quantumdot-polymer composite prepared therefrom, and an electronic deviceincluding the same are disclosed.

2. Description of the Related Art

By colloidal synthesis, the particle size of Quantum dots (QD) may berelatively freely and uniformly controlled. The QDs having a size ofless than or equal to about 10 nm may exhibit a more significant quantumconfinement effect as their size decreases and thereby their bandgapincreases. In this case, the energy density of the QDs may be enhanced.

The QDs are applicable for various display devices (e.g., LCD) in theform of a QD-polymer composite. For the application of the QD-polymercomposites in various devices, there remains a need to develop atechnique for patterning the quantum dot-polymer composite.

SUMMARY

An embodiment is related to a photosensitive composition capable ofpreparing a pattern of a quantum dot-polymer composite or a patternablequantum dot-polymer composite.

Another embodiment is related to a production method of theaforementioned photosensitive composition.

Another embodiment is related to a quantum dot-polymer compositeprepared from the aforementioned photosensitive composition.

Yet another embodiment provides a color filter including the quantumdot-polymer composite.

Yet another embodiment provides a display device including the quantumdot-polymer composite.

In an embodiment, a photosensitive composition includes:

a quantum dot dispersion;

a photopolymerizable monomer having a carbon-carbon double bond; and

a photoinitiator,

wherein the quantum dot dispersion includes an acid group-containingpolymer and a plurality of quantum dot dispersed in the acidgroup-containing polymer, and

wherein the acid group-containing polymer includes a copolymer of amonomer combination including a first monomer having a carboxylic acidgroup or a phosphonic acid group and a carbon-carbon double bond and asecond monomer having a carbon-carbon double bond and a hydrophobicgroup and not having a carboxylic acid group and a phosphonic acidgroup.

The quantum dot may include an organic ligand with a hydrophobic groupbound to a surface thereof. In some embodiments, the organic ligand doesnot include a photopolymerizable functional group such as a (meth)acrylmoiety.

The acid group-containing polymer may have an acid value of greater thanor equal to about 120 milligrams of KOH per gram and less than or equalto about 200 milligrams of KOH per gram.

The acid group-containing polymer may have an acid value of greater thanor equal to about 125 milligrams of KOH per gram and less than or equalto about 200 milligrams of KOH per gram.

The organic ligand may include RCOOH, RNH₂, R₂NH, R₃N, RSH, R₃PO, R₃P,ROH, RCOOR′, RPO(OH)₂, R₂POOH (wherein R and R′ are independently a C5to C24 aliphatic hydrocarbon group, a C5 to C20 alicyclic hydrocarbongroup, or a C5 to C20 aromatic hydrocarbon group), a polymeric organicligand, or a combination thereof.

The quantum dot may include a Group II-VI compound, a Group III-Vcompound, a Group IV-VI compound, a Group IV element or compound, aGroup I-III-VI compound, a Group I-II-IV-VI compound, or a combinationthereof.

In the photosensitive composition, the copolymer may include a firstrepeating unit derived from a first monomer and a second repeating unitderived from a second monomer, and

the first repeating unit may include a repeating unit represented byChemical Formula 1-1, a repeating unit represented by Chemical Formula1-2, or a combination thereof:

wherein

R¹ is hydrogen, a C1 to C3 alkyl group, or —(CH₂)_(n1)—COOH (wherein n1is 0 to 2),

R² is hydrogen, a C1 to C3 alkyl group, or —COOH,

L is a single bond, a C1 to C15 aliphatic hydrocarbon group, a C6 to C30aromatic hydrocarbon group, a C6 to C30 alicyclic hydrocarbon group, ora C1 to C15 aliphatic hydrocarbon group substituted with a C6 to C30aromatic hydrocarbon group or a C6 to C30 alicyclic hydrocarbon group,and

* indicates a portion connected to an adjacent atom;

wherein

R¹ is hydrogen, a C1 to C3 alkyl group, or —(CH₂)_(n1)—COOH (wherein nis 0 to 2),

R² is hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group, or a C1 to C15 aliphatichydrocarbon group substituted with a C6 to C30 aromatic hydrocarbongroup or a C6 to C30 alicyclic hydrocarbon group,

n is an integer of 1 to 3, and

* indicates a portion connected to an adjacent atom.

The second repeating unit may include a repeating unit represented byChemical Formula 2, a repeating unit represented by Chemical Formula 4,a repeating unit represented by Chemical Formula 5, a repeating unitrepresented by Chemical Formula A, or a combination thereof:

wherein

R¹ is hydrogen or a C1 to C3 alkyl group, R² is a C1 to C15 aliphatichydrocarbon group, a C6 to C30 aromatic hydrocarbon group, a C6 to C30alicyclic hydrocarbon group (for example, a cycloalkyl group such ascyclohexyl or norbornyl or a cycloalkenyl group such as norbornene), ora C1 to C15 aliphatic hydrocarbon group substituted with a C6 to C30aromatic hydrocarbon group or a C6 to C30 alicyclic hydrocarbon group,

R³ is hydrogen or a C1 to C3 alkyl group, and

* indicates a portion connected to an adjacent atom;

wherein

R¹ is hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group, or a C1 to C15 aliphatichydrocarbon group substituted with a C6 to C30 aromatic hydrocarbongroup or a C6 to C30 alicyclic hydrocarbon group,

R² is a C1 to C15 aliphatic hydrocarbon group, a C6 to C30 aromatichydrocarbon group, a C6 to C30 alicyclic hydrocarbon group (for example,a cycloalkyl group such as cyclohexyl or norbornyl or a cycloalkenylgroup such as norbornene), or a C1 to C15 aliphatic hydrocarbon groupsubstituted with a C6 to C30 aromatic hydrocarbon group or a C6 to C30alicyclic hydrocarbon group,

R³ is hydrogen or a C1 to C3 alkyl group,

n is an integer of 1 to 3, and

* indicates a portion connected to an adjacent atom;

wherein

each of R¹ and R² is independently hydrogen or a C1 to C3 alkyl group,

Ar is a substituted or unsubstituted C6 to C30 aromatic hydrocarbongroup or a substituted or unsubstituted C6 to C30 alicyclic hydrocarbongroup, and

* indicates a portion connected to an adjacent atom;

wherein

R¹ is hydrogen or a C1 to C3 alkyl group,

R² is a C1 to C15 aliphatic hydrocarbon group, a C6 to C30 aromatichydrocarbon group, a C6 to C30 alicyclic hydrocarbon group (for example,a cycloalkyl group such as cyclohexyl or norbornyl or a cycloalkenylgroup such as norbornene), or a C1 to C15 aliphatic hydrocarbon groupsubstituted with a C6 to C30 aromatic hydrocarbon group or a C6 to C30alicyclic hydrocarbon group,

R³ is hydrogen or a C1 to C3 alkyl group, and

* indicates a portion connected to an adjacent atom.

The monomer combination may further include a third monomer having acarbon-carbon double bond and a hydrophilic moiety and not having acarboxylic acid group and a phosphonic acid group.

The copolymer may include a third repeating unit derived from the thirdmonomer and the third repeating unit may be represented by ChemicalFormula 3:

wherein

each of R¹ and R² is independently hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group, or a C1 to C15 aliphatichydrocarbon group substituted with a C6 to C30 aromatic hydrocarbongroup or a C6 to C30 alicyclic hydrocarbon group,

Z is a hydroxyl group (—OH), a mercapto group (—SH), or an amino group(—NHR, wherein R is hydrogen or a C1 to C5 alkyl group), and

* indicates a portion connected to an adjacent atom.

In the acid group-containing polymer, an amount of the first repeatingunit may be greater than or equal to about 5 mole percent and less thanor equal to about 95 mole percent.

The acid group-containing polymer may be a copolymer of (meth)acrylicacid and the second and third monomer selected from alkyl(meth)acrylate,arylalkyl(meth)acrylate, hydroxyalkyl (meth)acrylate, and styrene.

A weight average molecular weight of the acid group-containing polymermay be greater than or equal to about 1,000 grams per mole and less thanor equal to about 100,000 grams per mole.

The photopolymerizable monomer including a carbon-carbon double bond mayinclude a diacrylate compound, a triacrylate compound, a tetraacrylatecompound, a pentaacrylate compound, a hexaacrylate compound, or acombination thereof.

The photosensitive composition may be developable by an alkali aqueoussolution.

The photosensitive composition may further include a solvent and it mayinclude:

about 1 percent by weight to about 40 percent by weight % of the quantumdots;

about 0.5 percent by weight % to about 35 percent by weight % of theacid group-containing polymer;

about 0.5 percent by weight % to about 30 percent by weight % of thephotopolymerizable monomer;

about 0.01 percent by weight % to about 10 percent by weight % of thephotoinitiator; and

a balance amount of the solvent based on the total weight of thecomposition.

The photosensitive composition may further include a light diffusingagent selected from the group consisting of a metal oxide particle, ametal particle, and a combination thereof.

The photosensitive composition may further include a dispersant for thelight diffusing agent or the quantum dots.

In another embodiment, a production method of the aforementionedphotosensitive composition includes:

dissolving an acid group-containing polymer in a solvent to prepare apolymer solution;

combining a plurality of quantum dots having an organic ligand bound toa surface thereof with the polymer solution to obtain a quantumdot-polymer dispersion; and

combining the quantum dot-polymer dispersion with at least one of aphotopolymerizable monomer having a carbon-carbon double bond, aphotoinitiator, and a solvent.

In another embodiment, a quantum dot-polymer composite includes:

a matrix including an acid group-containing polymer and a polymerizationproduct of a photopolymerizable monomer having a carbon-carbon doublebond; and

a plurality of quantum dots including an organic ligand that may boundto a surface thereof;

wherein the acid group-containing polymer includes a copolymer of amonomer combination including a first monomer having a carboxylic acidgroup or a phosphonic acid group and a carbon-carbon double bond and asecond monomer having a carbon-carbon double bond and a hydrophobicgroup and not having a carboxylic acid group and a phosphonic acidgroup; and

wherein the plurality of quantum dots are dispersed in the matrix.

The copolymer may be a linear polymer. The photopolymerizable monomermay include a monomer having at least three (meth)acrylate groups andthe polymerization product may include a crosslinked polymer.

The acid group-containing polymer may have an acid value of greater thanor equal to about 120 milligrams of KOH per gram and less than or equalto about 200 milligrams of KOH per gram.

The acid group-containing polymer may have an acid value of greater thanor equal to about 125 milligrams of KOH per gram and less than or equalto about 200 milligrams of KOH per gram.

The organic ligand may include a hydrophobic group and it may includeRCOOH, RNH₂, R₂NH, R₃N, RSH, R₃PO, R₃P, ROH, RCOOR′, RPO(OH)₂, R₂POOH(wherein R and R′ are independently a C5 to C24 aliphatic hydrocarbongroup, a C5 to C20 alicyclic hydrocarbon group, or a C5 to C20 aromatichydrocarbon group), a polymeric organic ligand, or a combinationthereof.

The quantum dot may include a Group II-VI compound, a Group III-Vcompound, a Group IV-VI compound, a Group IV compound, a Group I-III-VIcompound, a Group I-II-IV-VI compound, or a combination thereof.

The monomer combination may further include a third monomer having acarbon-carbon double bond and a hydrophilic moiety and not having acarboxylic acid group and a phosphonic acid group.

In the photosensitive composition,

the copolymer may include a first repeating unit derived from the firstmonomer and a second repeating unit derived from the second monomer, and

the first repeating unit may include a repeating unit represented byChemical Formula 1-1, a repeating unit represented by Chemical Formula1-2, or a combination thereof:

wherein

R¹ is hydrogen, a C1 to C3 alkyl group, or —(CH₂)_(n1)—COOH (wherein nis 0 to 2),

R² is hydrogen, a C1 to C3 alkyl group, or —COOH,

L is a single bond, a C1 to C15 aliphatic hydrocarbon group, a C6 to C30aromatic hydrocarbon group, a C6 to C30 alicyclic hydrocarbon group, ora C1 to C15 aliphatic hydrocarbon group substituted with a C6 to C30aromatic hydrocarbon group or a C6 to C30 alicyclic hydrocarbon group,and

* indicates a portion connected to an adjacent atom;

wherein

R¹ is hydrogen, a C1 to C3 alkyl group, or —(CH₂)_(n1)—COOH (wherein nis 0 to 2),

R² is hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group, or a C1 to C15 aliphatichydrocarbon group substituted with a C6 to C30 aromatic hydrocarbongroup or a C6 to C30 alicyclic hydrocarbon group,

n is an integer of 1 to 3, and

* indicates a portion connected to an adjacent atom.

The second repeating unit may include a repeating unit represented byChemical Formula 2, a repeating unit represented by Chemical Formula 4,a repeating unit represented by Chemical Formula 5, a repeating unitrepresented by Chemical Formula A, or a combination thereof:

wherein

R¹ is hydrogen or a C1 to C3 alkyl group,

R² is a C1 to C15 aliphatic hydrocarbon group, a C6 to C30 aromatichydrocarbon group, a C6 to C30 alicyclic hydrocarbon group, or a C1 toC15 aliphatic hydrocarbon group substituted with a C6 to C30 aromatichydrocarbon group or a C6 to C30 alicyclic hydrocarbon group, and

R³ is hydrogen or a C1 to C3 alkyl group, and

* indicates a portion connected to an adjacent atom;

wherein

R¹ is hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group, or a C1 to C15 aliphatichydrocarbon group substituted with a C6 to C30 aromatic hydrocarbongroup or a C6 to C30 alicyclic hydrocarbon group,

R² is a C1 to C15 aliphatic hydrocarbon group, a C6 to C30 aromatichydrocarbon group, a C6 to C30 alicyclic hydrocarbon group (for example,a cycloalkyl group such as cyclohexyl or norbornyl or a cycloalkenylgroup such as norbornene), or a C1 to C15 aliphatic hydrocarbon groupsubstituted with a C6 to C30 aromatic hydrocarbon group or a C6 to C30alicyclic hydrocarbon group,

R³ is hydrogen or a C1 to C3 alkyl group,

n is an integer of 1 to 3, and

* indicates a portion connected to an adjacent atom;

wherein

each of R¹ and R² is independently hydrogen or a C1 to C3 alkyl group,

Ar is a substituted or unsubstituted C6 to C30 aromatic hydrocarbongroup or a substituted or unsubstituted C6 to C30 alicyclic hydrocarbongroup, and

* indicates a portion connected to an adjacent atom;

wherein

R¹ is hydrogen or a C1 to C3 alkyl group,

R² is a C1 to C15 aliphatic hydrocarbon group, a C6 to C30 aromatichydrocarbon group, a C6 to C30 alicyclic hydrocarbon group (for example,a cycloalkyl group such as cyclohexyl or norbornyl or a cycloalkenylgroup such as norbornene), or a C1 to C15 aliphatic hydrocarbon groupsubstituted with a C6 to C30 aromatic hydrocarbon group or a C6 to C30alicyclic hydrocarbon group,

R³ is hydrogen or a C1 to C3 alkyl group, and

* indicates a portion connected to an adjacent atom.

The acid group-containing polymer may include a copolymer of a monomercombination that further includes a third monomer having a carbon-carbondouble bond and a hydrophilic moiety and not having a carboxylic acidgroup and a phosphonic acid group.

The copolymer may include a third repeating unit derived from the thirdmonomer, and the third repeating unit may be represented by ChemicalFormula 3:

wherein

each of R¹ and R² is independently hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group, or a C1 to C15 aliphatichydrocarbon group substituted with a C6 to C30 aromatic hydrocarbongroup or a C6 to C30 alicyclic hydrocarbon group,

Z is a hydroxyl group (—OH), a mercapto group (—SH), or an amino group(—NHR, wherein R is hydrogen or a C1 to C5 alkyl group), and

* indicates a portion connected to an adjacent atom.

In the acid group-containing polymer, an amount of the first repeatingunit may be greater than or equal to about 5 mole percent and less thanor equal to about 95 mole percent.

The acid group-containing polymer may include a copolymer of(meth)acrylic acid and at least one monomer selected fromalkyl(meth)acrylate, arylalkyl(meth)acrylate, hydroxyalkyl(meth)acrylate, and styrene.

The quantum dot-polymer composite may be a pattern.

Another embodiment provides a color filter including a quantumdot-polymer composite prepared from the photosensitive composition.

Yet another embodiment provides a display device including the quantumdot-polymer composite.

The aforementioned photosensitive composition may prepare a quantumdot-polymer composite pattern in an environmentally friendly manner. Thephotosensitive composition of the embodiments may be applied to aconventional photo-resist process without any additional surfacetreatment for the quantum dots. The pattern thus prepared may showenhanced stability even under heat-treatment carried out during thephoto-resist process.

BRIEF DESCRIPTION OF THE DRAWINGS

The present patent application contains at least one drawing executed incolor. Copies of this application with color drawing(s) will be providedby the Office upon request and payment of the necessary fee.

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a view showing a pattern forming process according to anembodiment to explain critical dimension uniformity;

FIG. 2 is a photographic image showing a quantum dot-binder dispersionprepared in Example 1;

FIG. 3 is an optical microscope photograph of the quantum dot-polymercomposite pattern prepared in Example 1;

FIG. 4 is photographic images showing that the patterns prepared inExample 1 emit green light and red light respectively when beingirradiated with blue light;

FIG. 5 is an electron-microscopic image showing quantum dots dispersedin the pattern prepared in Example 1;

FIG. 6 is a photographic image showing a mixture of the quantum dotcomposition prepared in Comparative Example 1;

FIG. 7 is a photographic image showing a quantum dot-binder dispersionprepared in Comparative Example 2;

FIG. 8 is an optical microscope photograph of the quantum dot-polymercomposite pattern prepared in Comparative Example 2;

FIG. 9 is a schematic illustration of a cross-section of a displaydevice according to a non-limiting embodiment; and

FIG. 10 is a schematic illustration of a cross-section of a displaydevice according to a non-limiting embodiment.

DETAILED DESCRIPTION

Advantages and characteristics of this disclosure, and a method forachieving the same, will become evident referring to the followingexemplary embodiments together with the drawings attached hereto. Theembodiments, may, however, be embodied in many different forms andshould not be construed as being limited to the embodiments set forthherein. Accordingly, the exemplary embodiments are merely describedbelow, by referring to the figures, to explain aspects of the presentinventive concept. Expressions such as “at least one of,” when precedinga list of elements, modify the entire list of elements and do not modifythe individual elements of the list. If not defined otherwise, all terms(including technical and scientific terms) in the specification may bedefined as commonly understood by one skilled in the art. The termsdefined in a generally-used dictionary should be interpreted as having ameaning that is consistent with their meaning in the context of therelevant art and the present disclosure, and may not be interpretedideally or overly broadly unless clearly defined. In addition, unlessexplicitly described to the contrary, the word “comprise” and variationssuch as “comprises” or “comprising”, and the word “include” andvariations such as “includes” or “including”, when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof. Therefore, the above words will be understood to implythe inclusion of stated elements but not the exclusion of any otherelements.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer, orsection from another element, component, region, layer, or section.Thus, a first element, component, region, layer, or section discussedbelow could be termed a second element, component, region, layer, orsection without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±10%, 5% of the stated value.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

Further, the singular includes the plural unless mentioned otherwise.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification.

It will be understood that when an element such as a layer, film,region, or substrate is referred to as being “on” another element, itcan be directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present.

As used herein, the term “alkyl group” refers to a group derived from astraight or branched chain saturated aliphatic hydrocarbon having thespecified number of carbon atoms and having a valence of at least one.

As used herein, the term “alkenyl group” may refer to a straight orbranched chain, monovalent hydrocarbon group having at least onecarbon-carbon double bond.

As used herein, the term “alkynyl group” refers to a straight orbranched chain, monovalent hydrocarbon group having at least onecarbon-carbon triple bond.

As used herein, the term “cycloalkyl group” refers to a monovalent grouphaving one or more saturated rings in which all ring members are carbon.

As used herein, the term “aryl”, which is used alone or in combination,refers to an aromatic hydrocarbon group containing at least one ring andhaving the specified number of carbon atoms. The term “aryl” may beconstrued as including a group with an aromatic ring fused to at leastone cycloalkyl ring.

As used herein, the term “arylalkyl group” refers to a substituted orunsubstituted aryl group covalently linked to an alkyl group that islinked to a compound.

As used herein, when a definition is not otherwise provided, the term“substituted” refers to a compound, a group, or a moiety wherein atleast one of hydrogen atoms thereof is substituted with a substituentselected from a 01 to C30 alkyl group, a C2 to C30 alkynyl group, a C6to C30 aryl group, a C7 to C30 alkylaryl group, a C1 to C30 alkoxygroup, a C1 to C30 heteroalkyl group, a C3 to C30 heteroalkylaryl group,a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 toC30 cycloalkynyl group, a C2 to C30 heterocycloalkyl group, a halogen(—F, —Cl, —Br, or —I), a hydroxy group (—OH), a nitro group (—NO₂), acyano group (—CN), an amino group (—NRR′, wherein R and R′ areindependently hydrogen or a C1 to C6 alkyl group), an azido group (—N₃),an amidino group (—C(═NH)NH₂), a hydrazino group (—NHNH₂), a hydrazonogroup (═N(NH₂), an aldehyde group (—C(═O)H), a carbamoyl group(—C(O)NH₂), a thiol group (—SH), an ester group (—C(═O)OR, wherein R isa C1 to C6 alkyl group or a C6 to C12 aryl group), a carboxylic acidgroup (—COOH) or a salt thereof (—C(═O)OM, wherein M is an organic orinorganic cation), a sulfonic acid group (—SO₃H) or a salt thereof(—SO₃M, wherein M is an organic or inorganic cation), a phosphoric acidgroup (—PO₃H₂) or a salt thereof (—PO₃MH or —PO₃M₂, wherein M is anorganic or inorganic cation), and a combination thereof.

When a group containing a specified number of carbon atoms issubstituted with any of the groups listed in the preceding paragraph,the number of carbon atoms in the resulting “substituted” group isdefined as the sum of the carbon atoms contained in the original(unsubstituted) group and the carbon atoms (if any) contained in thesubstituent. For example, when the term “substituted C1 to C20 alkyl”refers to a C1 to C20 alkyl group substituted with a C6 to C20 arylgroup, the total number of carbon atoms in the resulting arylsubstituted alkyl group is C7 to C40.

As used herein, the term “alkylene group” may refer to a straight orbranched saturated aliphatic hydrocarbon group having a valence of atleast two, optionally substituted with one or more substituents. As usedherein, the term “cycloalkylene group” may refer to a saturatedalicyclic hydrocarbon group having a valence of at least two, optionallysubstituted with one or more substituents. The term “arylene group” mayrefer to a functional group having a valence of at least two obtained byremoval of at least two hydrogens in an aromatic ring, optionallysubstituted with one or more substituents.

As used herein, the term “(meth)acrylate” refers to acrylate and/ormethacrylate.

As used herein, the term “hydrophobic group” refers to a group thatcauses a given compound including the same to show agglomeration in anaqueous solution and to have a tendency to repel water. For example, thehydrophobic group may include an aliphatic hydrocarbon group having acarbon number of greater than or equal to 2 (alkyl, alkenyl, alkynyl,etc.), an aromatic hydrocarbon group having a carbon number of greaterthan or equal to 6 (phenyl, naphthyl, aralkyl group, etc.), or analicyclic hydrocarbon group having a carbon number of greater than orequal to 5 (e.g., cycloalkyl group such as cyclohexyl or norbornyl or acycloalkenyl group such as norbornene, etc.). The hydrophobic groupsubstantially lacks an ability to make a hydrogen bond with an ambientmedium and is not substantially mixed with the medium as its polarity isnot matched with that of the medium.

As used herein, the term “visible light” refers to light having awavelength of about 390 nanometers (nm) to about 700 nm. As used herein,the term “UV light” refers to light having a wavelength of greater thanor equal to about 200 nm and less than about 390 nm.

As used herein, the term “dispersion” refers to a dispersion wherein adispersed phase is a solid and a continuous phase includes a liquid.

For example, the term “dispersion” may refer to a colloidal dispersionwherein the dispersed phase has a dimension of about 1 nm to about 1micrometer (μm).

As used herein, the term “group” refers to a group of Periodic Table.

As used herein, “Group II” refers to Group IIA and Group IIB, andexamples of Group II metal may be Cd, Zn, Hg, and Mg, but are notlimited thereto.

As used herein, “Group III” refers to Group IIIA and Group IIIB, andexamples of Group III metal may be Al, In, Ga, and TI, but are notlimited thereto.

As used herein, “Group IV” refers to Group IVA and Group IVB, andexamples of a Group IV metal may be Si, Ge, and Sn, but are not limitedthereto. As used herein, the term “metal” may include a semi-metal suchas Si.

As used herein, “Group I” refers to Group IA and Group IB, and examplesmay include Li, Na, K, Ru, and Cs, but are not limited thereto.

As used herein, “Group V” refers to Group VA, and examples may includeN, P, As, Sb, and Bi, but are not limited thereto.

As used herein, “Group VI” refers to Group VIA, and examples may includeS, Se, and Te, but are not limited thereto.

Hereinafter, the term “binder” or “acid group-containing binder” refersto the “acid group (e.g., carboxylic acid or phosphonic acid)-containingpolymer.”

In an embodiment, a photosensitive composition includes:

a plurality of quantum dots including an organic ligand with ahydrophobic moiety on a surface thereof;

an acid group-containing polymer;

a photopolymerizable monomer having a carbon-carbon double bond;

a photoinitiator; and

a solvent,

wherein the carboxy group-containing binder includes a copolymer of amonomer mixture including a first monomer having a carboxyl group and acarbon-carbon double bond and a second monomer having a carbon-carbondouble bond and a hydrophobic moiety and not having a carboxyl group.The plurality of quantum dots may be dispersed by the binder.

The photosensitive composition includes:

a quantum dot dispersion;

a photopolymerizable monomer having a carbon-carbon double bond; and

a photoinitiator.

The quantum dot dispersion includes an acid group-containing polymer anda plurality of quantum dots, which may include one or more quantum dot.The acid group-containing polymer includes a copolymer of a monomercombination including a first monomer having a carboxylic acid group(—CO₂H) or a phosphonic acid group (—PO₃H₂) and a carbon-carbon doublebond and a second monomer having a carbon-carbon double bond and ahydrophobic group and not having a carboxylic acid group and aphosphonic acid group. The quantum dots are dispersed (for example,separated from one another) by the binder. The quantum dot dispersionmay further include a solvent. In some embodiments, the photosensitivecomposition does not include a compound having at least two thiol groups(e.g., at its terminal ends).

The quantum dot (hereinafter also referred to as a semiconductornanocrystal) is not particularly limited, and may be prepared in anyknown method or is a commercially available. For example, the quantumdot may be a Group II-VI compound, a Group III-V compound, a Group IV-VIcompound, a Group IV element or compound, a Group I-III-VI compound, aGroup I-II-IV-VI compound, or a combination thereof.

The Group II-VI compound may be selected from:

a binary element compound selected from CdSe, CdTe, ZnS, ZnSe, ZnTe,ZnO, HgS, HgSe, HgTe, MgSe, MgS, and a combination thereof;

a ternary element compound selected from CdSeS, CdSeTe, CdSTe, ZnSeS,ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS,CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and a combinationthereof; and

a quaternary element compound selected from HgZnTeS, CdZnSeS, CdZnSeTe,CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and acombination thereof. The Group II-VI compound may further include aGroup III metal.

The Group III-V compound may be selected from:

a binary element compound selected from GaN, GaP, GaAs, GaSb, AlN, AlP,AlAs, AlSb, InN, InP, InAs, InSb, and a combination thereof;

a ternary element compound selected from GaNP, GaNAs, GaNSb, GaPAs,GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs,InPSb, InZnP, and a combination thereof; and

a quaternary element compound selected from GaAlNP, GaAlNAs, GaAlNSb,GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP,InAlNAs, InAlNSb, InAlPAs, InAlPSb, and a combination thereof. The GroupIII-V compound may further include a Group II metal (e.g., InZnP).

The Group IV-VI compound may be selected from:

a binary element compound selected from SnS, SnSe, SnTe, PbS, PbSe,PbTe, and a combination thereof;

a ternary element compound selected from SnSeS, SnSeTe, SnSTe, PbSeS,PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and a combination thereof; and

a quaternary element compound selected from SnPbSSe, SnPbSeTe, SnPbSTe,and a combination thereof.

Examples of the Group I-III-VI compound may include CuInSe₂, CuInS₂,CuInGaSe, and CuInGaS, but are not limited thereto.

Examples of the Group I-II-IV-VI compound may include CuZnSnSe andCuZnSnS, but are not limited thereto.

The Group IV element or compound may include:

a single-element selected from Si, Ge, and a combination thereof; and

a binary element compound selected from SiC, SiGe, and a combinationthereof.

The binary element compound, the ternary element compound or thequaternary element compound may respectively be included in a uniformconcentration in the particle or partially different concentrations inthe same particle. The semiconductor nanocrystal particle may have acore-shell structure wherein a first semiconductor nanocrystal issurrounded by a second semiconductor nanocrystal that is different fromthe first semiconductor nanocrystal. The interface between the core andthe shell may have a concentration gradient wherein the concentration ofan element of the shell decreases toward the core. In addition, thesemiconductor nanocrystal particle may have a semiconductor nanocrystalcore and a multi-layered shell surrounding the semiconductor nanocrystalcore. The core and multi-layered shell structure has at least two layersof the shell wherein each layer may be a single composition, an alloy,or the one having a concentration gradient.

In the semiconductor nanocrystal particle, the materials of the shellmay have a larger energy bandgap than that of the core, and thereby thesemiconductor nanocrystal may exhibit a quantum confinement effect moreeffectively. In case of a multi-layered shell type of semiconductornanocrystal particle, the bandgap of the material of an outer layer ofthe shell may be higher energy than that of the material of an innerlayer of the shell (a layer that is closer to the core). In this case,the semiconductor nanocrystal particle may emit light of a UV toinfrared wavelength range.

The semiconductor nanocrystal may have a quantum yield of greater thanor equal to about 10 percent (%), or greater than or equal to about 30%,for example, greater than or equal to about 50%, greater than or equalto about 60%, greater than or equal to about 70%, or greater than orequal to about 90%.

For use in display devices, the semiconductor nanocrystal may have anarrower FWHM so as to realize enhanced color purity or colorreproducibility. The semiconductor nanocrystal may have a FWHM of lessthan or equal to about 45 nm, for example less than or equal to about 40nm, or less than or equal to about 30 nm. While not wishing to be boundby theory, it is understood that within such ranges, a device includingthe nanocrystal may have enhanced color purity or improved colorreproducibility.

The quantum dot (i.e., the semiconductor nanocrystal particle) may havea particle diameter (the longest diameter for a non-spherically shapedparticle) of about 1 nm to about 100 nm. For example, the quantum dotmay have a particle diameter (the longest diameter for a non-sphericallyshaped particle) of about 1 nm to about 20 nm, for example, from 2 nm(or from 3 nm) to 15 nm.

The quantum dot may have a generally-used shape in this art, and is notparticularly limited. For example, the quantum dot may include variousthree-dimensional shapes such as spherical shape, elliptical shape,cubical shape, tetrahedral shape, pyramidal shape, octahedral shape,cylindrical shape, polygonal shape, multi-armed shape, or any of variouscommon regular and irregular shapes. The quantum dots may also havevarious vertical and horizontal cross-sectional shapes, for example,circular shape, triangular shape, quasi-triangular shape, triangularshape with semi-circles, triangular shape with one or more roundedcorners, square shape, rectangular shape, rectangular shape withsemi-circles, polygonal shape, or any of various common regular andirregular shapes. The quantum dots may be in the form of nanotubes,nanowires, nanofibers, nanoplate particles, a combination thereof, orthe like.

The quantum dot is commercially available or may be synthesized in anymethod known in the art. For example, several nano-sized quantum dotsmay be synthesized according to a wet chemical process. In the wetchemical process, precursors react in an organic solvent to grownanocrystal particles, and the organic solvent or a ligand compound maycoordinate (bound) to the surface of the semiconductor nanocrystal,thereby controlling the growth of the nanocrystal. Examples of theorganic solvent and ligand compound are known. The organic solventcoordinated to the surface of the quantum dot may affect stability of adevice, and thus excess organic materials that are not coordinated tothe surface of the quantum dot may be removed by pouring the quantum dotinto an excessive amount of a non-solvent, and centrifuging theresulting mixture. Examples of the non-solvent may be acetone, ethanol,methanol, and the like, but are not limited thereto. After the removalof extra organic materials, the amount of the organic materialscoordinated to the surface of the quantum dots may be less than or equalto about 50 percent by weight (wt %), for example, less than or equal toabout 30 wt %, less than or equal to about 20 wt %, or less than orequal to about 10 wt % based on the total weight of the quantum dots.The organic material may include a ligand compound, an organic solvent,or a combination thereof.

The quantum dot may have an organic ligand having a hydrophobic group,which is bonded to the surface of the quantum dot. In an embodiment, theorganic ligand may be a monofunctional organic ligand (i.e., an organicligand having only one functional group, which is bonded to the surfaceof the quantum dot). In another embodiment, the organic ligand having ahydrophobic group may include RCOOH, RNH₂, R₂NH, R₃N, RSH, R₃PO, R₃P,ROH, RCOOR′, RPO(OH)₂, R₂POOH (wherein R and R′ are independently a C5to C24 alkyl group, a C5 to C24 alkenyl group, or a C5 to C20 arylgroup), a polymeric organic ligand, or a combination thereof.

Examples of the organic ligand compound bonded the surface of thequantum dot may include:

thiol compounds such as methane thiol, ethane thiol, propane thiol,butane thiol, pentane thiol, hexane thiol, octane thiol, dodecane thiol,hexadecane thiol, octadecane thiol, or benzyl thiol;

amine compounds such as methane amine, ethylamine, propylamine,butylamine, pentylamine, hexylamine, octylamine, nonylamine, decylamine,dodecylamine, hexadecyl amine, octadecyl amine, dimethylamine, diethylamine, dipropyl amine, tributylamine, or trioctylamine;

carboxylic acid compounds such as methanoic acid, ethanoic acid,propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoicacid, octanoic acid, dodecanoic acid, hexadecanoic acid, octadecanoicacid, oleic acid, or benzoic acid;

phosphine compounds such as methyl phosphine, ethyl phosphine, propylphosphine, butyl phosphine, pentyl phosphine, octylphosphine, dioctylphosphine, diphenyl phosphine, triphenyl phosphine, tributylphosphine,or trioctylphosphine;

phosphine oxide compounds such as methyl phosphine oxide, ethylphosphine oxide, propyl phosphine oxide, butyl phosphine oxide, pentylphosphine oxide, diphenyl phosphine oxide, triphenyl phosphine oxide,tributyl phosphine oxide, octylphosphine oxide, dioctyl phosphine oxide,or trioctyl phosphine oxide;

a C5 to C20 alkyl phosphinic acid compounds such as hexylphosphinicacid, octylphosphinic acid, dodecanephosphinic acid,tetradecanephosphinic acid, hexadecanephosphinic acid, oroctadecanephosphinic acid; and the like, but are not limited thereto.

The quantum dot may include the hydrophobic organic ligand alone or as acombination of two or more organic ligands.

An amount of the quantum dot including the organic ligand may be greaterthan or equal to about 1 wt %, for example, greater than or equal toabout 5 wt %, or greater than or equal to about 10 wt %, based on thetotal amount of the composition. The amount of the quantum dot includingthe organic ligand may be less than or equal to about 40 wt %, forexample, less than or equal to about 35 wt %, based on the total amountof the composition. In some embodiments, the amount of the quantum dotincluding the organic ligand may be about 5 wt % to 40 wt %, based on atotal weight of solid contents (non-volatile components) of thecompositions.

The quantum dot may have a theoretical quantum yield (QY) of about 100%,and may emit light having high color purity (e.g., a full width at halfmaximum (FWHM) of less than or equal to about 40 nm), and thus it mayachieve the enhanced luminous efficiency and the improved colorreproducibility. Meanwhile, it is expected that using a photoluminescenttype of color filter instead of the absorption type of color filter maywiden the viewing angle and improve the luminance. Accordingly, whilenot wishing to be bound by theory, it is believed that using a colorfilter including a quantum dot polymer composite may allow realizing adisplay having high brightness, a wide viewing angle, and high colorreproducibility. In order to realize the aforementioned properties,however, it may be required to well-disperse a relatively large numberof quantum dots in the polymer composite.

As a method of forming a pattern including quantum dots in conventionalarts, U.S. Pat. No. 7,199,393 discloses that quantum dots having aphotosensitive functional group on the surface thereof are used in apatterning method, the entire content of which is incorporated herein byreference. In the disclosed method, a photosensitive functional group isintroduced onto the surface of a quantum dot and subjected tophotopolymerization, if desired together with a photopolymerizablemonomer, to prepare a quantum dot-polymer composite pattern. But thedisclosed method requires an additional process of a surface treatmentof quantum dots and needs to use an organic solvent to form a patternduring a developing process.

On the other hand, when the quantum dots (e.g., in which organic ligandis bound to the surface) are mixed with the alkali-developablephotoresist without performing any surface treatment in an attempt toprovide an alkali-developable quantum dot-polymer composite pattern,they are not dispersed well or are even agglomerated because the quantumdots have poor compatibility with the conventional photoresist. In orderfor the patterned quantum dot-polymer composite to be applied in a colorfilter, a large amount of quantum dots should be able to be included inthe composite. When the quantum dots cannot be dispersed in thecomposition, it becomes impossible to provide a uniform pattern.

In the photosensitive composition according to an embodiment, thequantum dot including an organic ligand (e.g., having a hydrophobicgroup) bonded to the surface is first dispersed in the solution of theacid group-containing binder having a hydrophobic group. The obtainedquantum dot-binder dispersion is then mixed with the other componentsfor a photoresist. As a result, the quantum dots may be well dispersedin the alkali-developable photoresist. Therefore, in case of thephotosensitive composition according to an embodiment, a relativelylarge amount of the quantum dots may be well dispersed in thephotoresist composition. Without wishing to be bound by any theory, itis understood that when the quantum dots are dispersed in the solutionof the acid group-containing binder having a hydrophobic group, thebinder may facilitate the formation of the dispersion including thequantum dots, and the quantum dots dispersed with the help of the bindermay maintain their dispersed state even when they constitute aphotoresist composition.

Therefore, the photosensitive composition of the embodiments includes aquantum dot dispersion that includes an acid group-containing binder anda plurality of the quantum dots dispersed (e.g., separated from oneanother) in the binder. The acid group-containing binder may include acopolymer of a monomer combination including the first monomer having acarboxylic acid group or a phosphonic acid group and a carbon-carbondouble bond and the second monomer having a carbon-carbon double bondand a hydrophobic group but including no carboxylic acid group and nophosphonic acid group.

As the photosensitive composition according to an embodiment may providea quantum dot-polymer composite pattern including the quantum dot withno photo-polymerizable functional group (e.g., carbon-carbon double bondsuch as (meth)acrylate), no surface treatment for the quantum dotsurface is necessary. In addition, a developing process for a patternprepared from the aforementioned photosensitive composition does notrequire a use of an organic solvent such as toluene or NMP in thedeveloping process.

Examples of the first monomer may include, but are not limited to,acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaricacid, 3-butenoic acid, carboxylic acid vinyl ester compounds such asvinyl acetate, and vinyl benzoate. The first monomer may include one ormore compounds.

Examples of the second monomer may include, but are not limited to:

alkenyl aromatic compounds such as styrene, α-methyl styrene, vinyltoluene, or vinyl benzyl methyl ether;

unsaturated carboxylic acid ester compounds such as methyl acrylate,methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate,butyl methacrylate, benzyl acrylate, benzyl methacrylate, cyclohexylacrylate, cyclohexyl methacrylate, phenyl acrylate, or phenylmethacrylate;

unsaturated carboxylic acid amino alkyl ester compounds such as2-dimethyl amino ethyl acrylate, or 2-dimethyl amino ethyl methacrylate;

maleimides such as N-phenylmaleimide, N-benzylmaleimide,N-alkylmaleimide;

unsaturated carboxylic acid glycidyl ester compounds such as glycidylacrylate or glycidyl methacrylate;

vinyl cyanide compounds such as acrylonitrile or methacrylonitrile; and

unsaturated amide compounds such as acrylamide or methacrylamide, butare not limited thereto.

As the second monomer, at least one compound may be used.

The acid group-containing binder may have an acid value of greater thanabout 120 milligrams of KOH per gram (mg KOH/g) in order to dispersequantum dots, but the acid value may vary depending on a chemicalstructure thereof (e.g., a chemical structure of a main chain or ahydrophobic group at the side chain). In some embodiments, the acidgroup-containing binder may have an acid value of greater than or equalto about 70 mg KOH/g, greater than or equal to about 80 mg KOH/g,greater than or equal to about 90 mg KOH/g, greater than or equal toabout 100 mg KOH/g, or greater than or equal to about 110 mg KOH/g. Insome embodiments, the acid group-containing binder may have an acidvalue of greater than or equal to about 125 mg KOH/g or an acid value ofgreater than or equal to about 130 mg KOH/g, The acid group-containingbinder may have an acid value of, for example, less than or equal toabout 200 mg KOH/g, for example, less than or equal to about 190 mgKOH/g, less than or equal to about 180 mg KOH/g, or less than or equalto about 160 mg KOH/g, but it is not limited thereto. While not wishingto be bound by theory, it is understood that when the quantum dots aremixed with a solution of a binder having the acid value within theaforementioned range to provide a quantum dot-binder dispersion, theobtained quantum dot-binder dispersion may have the improvedcompatibility with the other components for the photoresist (e.g.,photopolymerizable monomer, photoinitiator, solvent, etc.), and therebythe quantum dots may be well dispersed in the final composition (i.e.,photoresist composition) to form a pattern. In an embodiment, the acidgroup-containing binder may have an acid value of about 100 mg KOH/g toabout 200 mg KOH/g.

The acid group-containing binder may include a copolymer of a monomercombination that includes the first and second monomers, and may furtherinclude a third monomer having a carbon-carbon double bond and ahydrophilic moiety and not having a carboxylic acid group and aphosphonic acid group.

Examples of the third monomer may include 2-hydroxy ethyl acrylate,2-hydroxy ethyl methacrylate, 2-hydroxy butyl acrylate, 2-hydroxy butylmethacrylate, 2-amino ethyl acrylate, and 2-amino ethyl methacrylate,but are not limited thereto. The third monomer may include one or morecompounds.

The first repeating unit may include a repeating unit represented byChemical Formula 1-1, a repeating unit represented by Chemical Formula1-2, or a combination thereof:

wherein

R¹ is hydrogen, a C1 to C3 alkyl group, or —(CH₂)_(n1)—COOH (wherein n1is 0 to 2),

R² is hydrogen, a C1 to C3 alkyl group, or —COOH,

L is a single bond, a C1 to C15 aliphatic hydrocarbon group such as a C1to C3 alkylene group, a C6 to C30 aromatic hydrocarbon group such as aC6 to C12 arylene group, a C6 to C30 alicyclic hydrocarbon group such asa cycloalkylene group (e.g. a cyclohexylene or a norbornane moiety), acycloalkenylene group (e.g., a norbornene moiety) and the like, or a C1to C15 aliphatic hydrocarbon group substituted with a C6 to C30 aromatichydrocarbon group or a C6 to C30 alicyclic hydrocarbon group, and

* indicates a portion linked to an adjacent atom;

wherein

R¹ is hydrogen, a C1 to C3 alkyl group, or —(CH₂)_(n1)—COOH (wherein n1is 0 to 2),

R² is hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group (e.g., a cycloalkylenegroup such as a cyclohexylene or a norbornane moiety or cycloalkenylenegroup such as a norbornene moiety), or a C1 to C15 aliphatic hydrocarbongroup substituted with a C6 to C30 aromatic hydrocarbon group or a C6 toC30 alicyclic hydrocarbon group,

n is an integer of 1 to 3, and

* indicates a portion linked to an adjacent atom.

The second repeating unit may include a repeating unit represented byChemical Formula 2, a repeating unit represented by Chemical Formula 4,a repeating unit represented by Chemical Formula 5, a repeating unitrepresented by Chemical Formula A, or a combination thereof:

wherein

R¹ is hydrogen or a C1 to C3 alkyl group,

R² is a C1 to C15 aliphatic hydrocarbon group (e.g., a C1 to C15 alkylgroup such as methyl, ethyl, propyl, and the like), a C6 to C30 aromatichydrocarbon group (a C6 to C24 aryl group such as a phenyl group, anaphthyl group or the like), a C6 to C30 alicyclic hydrocarbon groupsuch as a cycloalkyl group (e.g., a cyclohexyl group, a norbornyl group,or the like), or a C1 to C15 aliphatic hydrocarbon group substitutedwith a C6 to C30 aromatic hydrocarbon group or a C6 to C30 alicyclichydrocarbon group (e.g., an arylalkyl group),

R³ is hydrogen or a C1 to C3 alkyl group, and

* indicates a portion linked to an adjacent atom;

wherein

R¹ is hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group (e.g., a cycloalkylenegroup such as a cyclohexylene or a norbornane moiety or acycloalkenylene group such as a norbornene moiety), or a C1 to C15aliphatic hydrocarbon group substituted with a C6 to C30 aromatichydrocarbon group or a C6 to C30 alicyclic hydrocarbon group,

R² is a 01 to C15 aliphatic hydrocarbon group (e.g., a C1 to C15 alkylgroup such as methyl, ethyl, propyl, and the like), a C6 to C30 aromatichydrocarbon group (e.g., a C6 to C24 aryl group such as a phenyl group,a naphthyl group, or the like), a C6 to C30 alicyclic hydrocarbon groupsuch as a cycloalkyl group (e.g., a cyclohexyl group, a norbornyl group,or the like), or a C1 to C15 aliphatic hydrocarbon group substitutedwith a C6 to C30 aromatic hydrocarbon group or a C6 to C30 alicyclichydrocarbon group (e.g., an arylalkyl group),

R³ is hydrogen or a C1 to C3 alkyl group,

n is an integer of 1 to 3, and

* indicates a portion linked to an adjacent atom;

wherein

each of R¹ and R² is independently hydrogen or a C1 to C3 alkyl group,

Ar is a substituted or unsubstituted C6 to C30 aromatic hydrocarbongroup (e.g., an aryl group such as phenyl and an arylalkyl group such asbenzyl and the like), or a substituted or unsubstituted C6 to C30alicyclic hydrocarbon group, and

* indicates a portion linked to an adjacent atom;

wherein

R¹ is hydrogen or a C1 to C3 alkyl group,

R² is a C1 to C15 aliphatic hydrocarbon group, a C6 to C30 aromatichydrocarbon group, a C6 to C30 alicyclic hydrocarbon group (for example,a cycloalkyl group or a cycloalkenyl group such as norbornene), or a C1to C15 aliphatic hydrocarbon group substituted with a C6 to C30 aromatichydrocarbon group or a C6 to C30 alicyclic hydrocarbon group,

R³ is hydrogen or a C1 to C3 alkyl group, and

* indicates a portion linked to an adjacent atom.

The copolymer may further include a third repeating unit derived from athird monomer, and the third repeating unit may be represented byChemical Formula 3:

wherein

each of R¹ and R² is independently hydrogen or a C1 to C3 alkyl group,

L is a C1 to C15 alkylene group, a C1 to C15 alkylene group wherein atleast one methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—,a C6 to C30 aromatic hydrocarbon group such as a C6 to C30 arylenegroup, a C6 to C30 alicyclic hydrocarbon group (e.g., a cycloalkylenegroup such as a cyclohexylene or a norbornane moiety or acycloalkenylene group such as a norbornene moiety), or a C1 to C15aliphatic hydrocarbon group substituted with a C6 to C30 aromatichydrocarbon group or a C6 to C30 alicyclic hydrocarbon group,

Z is a hydroxyl group (—OH), a mercapto group (—SH), or an amino group(—NHR, wherein R is hydrogen or a C1 to C5 alkyl group), and

* indicates a portion linked to an adjacent atom.

In an embodiment, the acid group-containing binder may include acopolymer of (meth)acrylic acid (i.e., the first monomer) and at leastone of the second and third monomer selected from alkyl(meth)acrylate,arylalkyl(meth)acrylate, hydroxyalkyl (meth)acrylate, and styrene.

In the acid group-containing binder, an amount of the first repeatingunit derived from the first monomer may be greater than or equal toabout 5 mole percent (mol %), for example, greater than or equal toabout 6 mol %, greater than or equal to about 7 mol %, greater than orequal to about 8 mol %, greater than or equal to about 9 mol %, greaterthan or equal to about 10 mol %, greater than or equal to about 15 mol%, greater than or equal to about 25 mol %, or greater than or equal toabout 35 mol %. In the acid group-containing binder, an amount of thefirst repeating unit may be less than or equal to about 95 mol %, forexample, less than or equal to about 94 mol %, less than or equal toabout 93 mol %, less than or equal to about 92 mol %, less than or equalto about 91 mol %, less than or equal to about 90 mol %, less than orequal to about 89 mol %, less than or equal to about 88 mol %, less thanor equal to about 87 mol %, less than or equal to about 86 mol %, lessthan or equal to about 85 mol %, less than or equal to about 80 mol %,less than or equal to about 70 mol %, less than or equal to about 65 mol%, less than or equal to about 45 mol %, less than or equal to about 35mol %, or less than or equal to about 25 mol %.

In the acid group-containing binder, an amount of the second repeatingunit derived from the second monomer may be may be greater than or equalto about 5 mol %, for example, greater than or equal to about 6 mol %,greater than or equal to about 7 mol %, greater than or equal to about 8mol %, greater than or equal to about 9 mol %, greater than or equal toabout 10 mol %, greater than or equal to about 15 mol %, greater than orequal to about 25 mol %, or greater than or equal to about 35 mol %. Inthe acid group-containing binder, an amount of the second repeating unitmay be less than or equal to about 95 mol %, for example, less than orequal to about 94 mol %, less than or equal to about 93 mol %, less thanor equal to about 92 mol %, less than or equal to about 91 mol %, lessthan or equal to about 90 mol %, less than or equal to about 89 mol %,less than or equal to about 88 mol %, less than or equal to about 87 mol%, less than or equal to about 86 mol %, less than or equal to about 85mol %, less than or equal to about 80 mol %, less than or equal to about70 mol %, less than or equal to about 65 mol %, less than or equal toabout 40 mol %, less than or equal to about 35 mol %, or less than orequal to about 25 mol %.

In the acid group-containing binder, an amount of the third repeatingunit derived from the third monomer may be greater than or equal toabout 1 mol %, for example, greater than or equal to about 5 mol %,greater than or equal to about 10 mol %, or greater than or equal toabout 15 mol %. In the acid group-containing binder, an amount of thethird repeating unit may be less than or equal to about 30 mol %, forexample, less than or equal to about 25 mol %, less than or equal toabout 20 mol %, less than or equal to about 18 mol %, less than or equalto about 15 mol %, or less than or equal to about 10 mol %.

The acid group-containing binder may include a copolymer of a(meth)acrylic acid, and at least one monomer selected from analkyl(meth)acrylate, an arylalkyl(meth)acrylate, a hydroxyalkyl(meth)acrylate, and styrene. For example, the acid group-containingbinder may be a methacrylic acid/methyl methacrylate copolymer, amethacrylic acid/benzyl methacrylate copolymer, a methacrylicacid/benzyl methacrylate/styrene copolymer, a methacrylic acid/benzylmethacrylate/2-hydroxy ethyl methacrylate copolymer, or a methacrylicacid/benzyl methacrylate/styrene/2-hydroxy ethyl methacrylate copolymer.

The acid group-containing binder may have a weight average molecularweight of greater than or equal to about 1,000 grams per mole (g/mol),for example, greater than or equal to about 2,000 g/mol, greater than orequal to about 3,000 g/mol, or greater than or equal to about 5,000g/mol. The acid group-containing binder may have a weight averagemolecular weight of less than or equal to about 100,000 g/mol, forexample, less than or equal to about 50,000 g/mol. While not wishing tobe bound by theory, it is understood that within the foregoing ranges,more improved developability may be ensured.

In the photosensitive composition, an amount of the acidgroup-containing binder may be greater than or equal to about 0.5 wt %,for example, greater than or equal to about 1 wt %, greater than orequal to about 5 wt %, greater than or equal to about 10 wt %, greaterthan or equal to about 15 wt %, or greater than or equal to about 20 wt% based on the total weight of the composition. An amount of the acidgroup-containing binder may be less than or equal to about 40 wt %, forexample, less than or equal to about 30 wt % based on the total weightof the composition. In an embodiment, an amount of the acidgroup-containing binder may be 5 to 40 wt % based on the total weight ofsolids (i.e., non-volatiles) of the composition. While not wishing to bebound by theory, it is understood that within the aforementioned range,appropriate developability and improved processability may beaccomplished in a subsequent pattern forming process while ensuringdispersibility of the quantum dots.

The photosensitive composition according to an embodiment includes aphotopolymerizable monomer having at least one (e.g., two, three, four,five, six, or more) carbon-carbon double bond (e.g., an acrylate groupor a methacrylate group). Types of the photopolymerizable monomer arenot particularly limited as long as they include a carbon-carbon doublebond and may be polymerized by light. For example, thephotopolymerizable monomer may be a monomer or an oligomer that may beused in a photosensitive composition. The photopolymerizable monomer mayinclude a monofunctional or multi-functional ester of (meth)acrylic acidhaving at least one ethylenic unsaturated double bond. For example, thephotopolymerizable monomer may include a vinyl monomer, an unsaturatedethylenic oligomer, a homopolymer thereof, a copolymer of theunsaturated ethylenic oligomer and an ethylenic unsaturated monomer, ora combination thereof. Examples of the photopolymerizable monomer mayinclude, but are not limited to, alkyl (meth)acrylate, ethylene glycoldi(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritoldi(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritoltetra(meth)acrylate, dipentaerythritol di(meth)acrylate,dipentaerythritol tri(meth)acrylate, dipentaerythritolpenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, bisphenol Aepoxyacrylate, bisphenol A di(meth)acrylate, trimethylolpropanetri(meth)acrylate, ethylene glycol monomethyl ether (meth)acrylate,novolacepoxy (meth)acrylate, diethylene glycol di(meth)acrylate,triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate,tris(meth)acryloyloxyethyl phosphate, and the like. Thephotopolymerizable monomer of the embodiments may include adi(meth)acrylate compound, a tri(meth)acrylate compound, atetra(meth)acrylate compound, a penta(meth)acrylate compound, ahexa(meth) acrylate compound, or a combination thereof.

In the photosensitive composition, the amount of the photopolymerizablemonomer may be greater than or equal to about 0.5 wt %, for example,greater than or equal to about 1 wt %, or greater than or equal to about2 wt % with respect to a total amount of the composition. The amount ofthe photopolymerizable monomer may be less than or equal to about 30 wt%, for example less than or equal to about 25 wt %, less than or equalto about 20 wt %, the amount of the photopolymerizable monomer may be 10wt % with respect to a total amount of the composition.

The photosensitive composition may include a photopolymerizationinitiator. Types of the photopolymerization initiator are notparticularly limited, and may be selected appropriately. For example,the available photopolymerization initiator may include a triazinecompound, an acetophenone compound, a benzophenone compound, athioxanthone compound, a benzoin compound, an oxime compound, or acombination thereof, but it is not limited thereto.

Examples of the triazine compound may include2,4,6-trichloro-s-triazine,2-phenyl-4,6-bis(trichloromethyl)-s-triazine,2-(3′,4′-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine,2-(4′-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine,2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine,2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine,2-biphenyl-4,6-bis(trichloromethyl)-s-triazine,2,4-bis(trichloromethyl)-6-styryl-s-triazine,2-(naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine,2-(4-methoxynaphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine,2,4-trichloromethyl(piperonyl)-6-triazine, and 2,4-trichloromethyl(4′-methoxystyryl)-6-triazine, but are not limited thereto.

Examples of the acetophenone compound may be 2,2′-diethoxyacetophenone,2,2′-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone,p-t-butyltrichloro acetophenone, p-t-butyldichloro acetophenone,4-chloroacetophenone, 2,2′-dichloro-4-phenoxyacetophenone,2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and thelike, but are not limited thereto.

Examples of the benzophenone compound may be benzophenone, benzoylbenzoate, benzoyl methyl benzoate, 4-phenyl benzophenone,hydroxybenzophenone, acrylated benzophenone,4,4′-bis(dimethylamino)benzophenone, 4,4′-dichlorobenzophenone,3,3′-dimethyl-2-methoxybenzophenone, and the like, but are not limitedthereto.

Examples of the thioxanthone compound may be thioxanthone, 2-methylthioxanthone, 2-isopropyl thioxanthone, 2,4-diethyl thioxanthone,2,4-di-iso-propyl thioxanthone, 2-chlorothioxanthone, and the like, butare not limited thereto.

Examples of the benzoin compound may include benzoin, benzoin methylether, benzoin ethyl ether, benzoin iso-propyl ether, benzoin iso-butylether, benzyl dimethyl ketal, and the like, but are not limited thereto.

Examples of the oxime compound may be2-(o-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione,1-(o-acetyloxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone,and the like, but are not limited thereto.

The photopolymerization initiator may also be a carbazole compound, adiketone compound, a sulfonium borate compound, a diazo compound, adi-imidazole compound, and the like, in addition to thephotopolymerization initiators.

In the photosensitive composition, an amount of the photoinitiator maybe greater than or equal to about 0.01 wt %, for example, greater thanor equal to about 0.1 wt %, or greater than or equal to about 1 wt %,based on the total weight of the composition. The amount of thephotoinitiator may be less than or equal to about 10 wt %, for example,less than or equal to about 5 wt %, based on the total weight of thecomposition. In an embodiment, the amount of the photoinitiator may beabout 0.05 to about 10 wt % based on the total weight of solids (i.e.,non-volatiles) of the composition. While not wishing to be bound bytheory, it is understood that within the aforementioned ranges, adesirable pattern may be formed.

If desired, the photosensitive composition may further include variousadditives such as a light diffusing agent, a leveling agent, or acoupling agent in addition to the aforementioned components. The amountof the additive is not particularly limited, and may be selected withinan appropriate range wherein the additive does not cause an adverseeffect on the photosensitive composition and the pattern obtainedtherefrom.

The light diffusing agent may increase a refractive index of thecomposition in order to increase a chance of the incident light to meetwith quantum dots. The light diffusing agent may include inorganic oxideparticles such as alumina, silica, zirconia, titanium oxideparticulates, or zinc oxide, and metal particles such as gold, silver,copper, or platinum, but is not limited thereto.

The leveling agent is aimed to prevent stains or spots and to improveplanarization and leveling characteristics of a film, and examplesthereof may include the following but are not limited thereto.

A fluorine-containing leveling agent may include commercial products,for example BM-1000® and BM-1100® of BM Chemie Inc.; MEGAFACE F 142D®, F172®, F 173®, and F 183® of Dainippon Ink Kagaku Kogyo Co., Ltd.;FC-135®, FC-170C®, FC-430®, and FC-431® of Sumitomo 3M Co., Ltd.;SURFLON S-112®, SURFLON S-113®, SURFLON S-131®, SURFLON S-141®, andSURFLON S-145® of Asahi Glass Co., Ltd.; and SH-28PA®, SH-190®, SH-193®,SZ-6032®, SF-8428°, and the like of Toray Silicone Co., Ltd.

Types and amounts of the additives may be adjusted as necessary.

The coupling agent is aimed to increase adherence with respect to thesubstrate and examples thereof may include a silane-containing couplingagent. Examples of the silane-containing coupling agent may be vinyltrimethoxysilane, vinyl tris(2-methoxyethoxy)silane, 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxy cyclohexyl)ethyl trimethoxysilane,3-chloropropyl methyldimethoxysilane, 3-chloropropyl trimethoxysilane,3-methacryloxylpropyl trimethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like.

The photosensitive composition may include a solvent. The solvent may beincluded in the quantum dot dispersion. An amount of the solvent may bedetermined based on the amounts of the above main components (i.e., theorganic ligand-containing quantum dots, the acid group-containingbinder, the photopolymerizable monomer combination, and thephotoinitiator), and additives. The composition may include the solventin such an amount that the remaining amount of the composition otherthan the amounts of the solid (i.e., non-volatiles) components is theamount of the solvent. The solvent may be selected appropriately basedon its affinity for other components (e.g., the binder, thephotopolymerizable monomer, the photoinitiator, and other additives),its affinity for the alkali developing solution, and its boiling point.Examples of the solvent may be:

ethyl 3-ethoxy propionate;

an ethylene glycol such as ethylene glycol, diethylene glycol, orpolyethylene glycol;

a glycol ether such as ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, diethylene glycol monomethyl ether, ethylene glycoldiethyl ether, and diethylene glycol dimethyl ether;

a glycol ether acetate such as ethylene glycol acetate, ethylene glycolmonoethyl ether acetate, diethylene glycol monoethyl ether acetate, anddiethylene glycol monobutyl ether acetate;

a propylene glycol such as propylene glycol;

a propylene glycol ether such as propylene glycol monomethyl ether,propylene glycol monoethyl ether, propylene glycol monopropyl ether,propylene glycol monobutyl ether, propylene glycol dimethyl ether,dipropylene glycol dimethyl ether, propylene glycol diethyl ether, anddipropylene glycol diethyl ether;

a propylene glycol ether acetate such as propylene glycol monomethylether acetate and dipropylene glycol monoethyl ether acetate;

an amide such as N-methylpyrrolidone, dimethyl formamide, and dimethylacetamide;

a ketone such as methyl ethyl ketone (MEK), methyl iso-butyl ketone(MIBK), and cyclohexanone;

a petroleum product such as toluene, xylene, and solvent naphtha;

an ester such as ethyl acetate, butyl acetate, and ethyl lactate; anether such as diethyl ether, dipropyl ether, and dibutyl ether;

and any combinations thereof.

A method of preparing a photosensitive composition according to anembodiment includes:

dissolving the acid group-containing binder in the solvent to prepare abinder solution;

dispersing a plurality of quantum dots having an organic ligand bondedto a surface thereof in the binder solution to obtain a quantumdot-binder dispersion; and

combining the quantum dot-binder dispersion with at least one selectedfrom a photoinitiator, a photopolymerizable monomer, and a solvent.

A mixing manner is not particularly limited, and may be appropriatelyselected. For example, each component may be mixed sequentially orsimultaneously.

The method may further include selecting quantum dots including anorganic ligand bonded to the surface thereof, and selecting a bindercapable of dispersing the quantum dots (e.g., an acid group-containingbinder). In the step of selecting the binder, the binder may be an acidgroup-containing binder, the acid group-containing binder may be acopolymer of a monomer combination including a first monomer having acarboxylic acid group or a phosphonic acid group and a carbon-carbondouble bond and a second monomer having a carbon-carbon double bond anda hydrophobic group and not having a carboxylic acid group and aphosphonic acid group. A chemical structure and an acid value of thecopolymer may be considered in this step.

Details of the quantum dots, the acid group-containing binder, thephotopolymerizable monomer, and the photoinitiator are the same as setforth above.

The photosensitive composition may be developable with an alkalineaqueous solution, and thus a quantum dot-polymer composite pattern maybe patterned from the photosensitive composition without using anorganic solvent developing solution.

A non-limiting method of forming a pattern is explained referring toFIG. 1.

First, the photosensitive composition is coated on a predeterminedsubstrate (e.g., a glass substrate or a glass substrate coated with apredetermined thickness of SiN_(x) (protective layer) (e.g., 500 to1,500 Angstroms (Å) of the protective layer)) in an appropriate mannersuch as spin coating, slit coating, and the like to form a film of apredetermined thickness (e.g., a thickness of 3 to 30 micrometers, μm).The formed film may be pre-baked, if desired. The specific conditions ofpre-baking such as temperature, time, and atmosphere are known in theart and may be appropriately selected.

The formed (or optionally, pre-baked) film is exposed to light of apredetermined wavelength under a mask having a predetermined pattern.The wavelength and the intensity of light may be selected based on thetypes and the amounts of the photoinitiator, the types and the amountsof quantum dots, or the like.

The exposed film is treated with an alkali developing solution, andthereby the unexposed region in the film is dissolved to provide adesirable pattern. The obtained pattern may be post-baked, if desired,to improve crack resistance and solvent resistance of the pattern, forexample, at a temperature of about 150° C. to about 230° C. for apredetermined time (e.g., greater than or equal to about 10 min orgreater than or equal to about 20 min).

When a quantum dot-polymer composite obtained from the photosensitivecomposition is used as a color filter, two or three types ofphotosensitive compositions each including red quantum dots, greenquantum dots, (or optionally, blue quantum dots) are prepared, and thepatterning process is repeated as many times as needed for eachcomposition to provide a quantum dot-polymer composite having adesirable pattern.

When the quantum dot-polymer composite obtained from the photosensitivecomposition is used as a color filter, two types of photosensitivecompositions including red quantum dots and green quantum dots,respectively, may be prepared, and the patterning process may berepeated as many times as needed for each composition to provide aquantum dot-polymer composite having a desirable pattern.

Another embodiment provides a quantum dot-polymer composite, whichincludes:

a matrix including an acid group-containing polymer and a polymerizationproduct of a photopolymerizable monomer having a carbon-carbon doublebond; and

a plurality of quantum dots including an organic ligand bonded to asurface thereof;

wherein the acid group-containing polymer includes a copolymer of amonomer combination including a first monomer having a carboxylic acidgroup or a phosphonic acid group and a carbon-carbon double bond and asecond monomer having a carbon-carbon double bond and a hydrophobicgroup and not having a carboxylic acid group and a phosphonic acidgroup; and

the plurality of quantum dots are dispersed (e.g., separated from oneanother) in the matrix (e.g., without agglomeration).

The composite may be a pattern.

Details of the quantum dots, the binder, the photopolymerizable monomer,and the like are the same as set forth above. The copolymer may be alinear polymer. The photopolymerizable monomer may include a monomerhaving at least three (meth)acrylate groups and the polymerizationproduct may include a crosslinked polymer.

In some embodiments, a color filter includes the quantum dot-polymercomposite or a pattern thereof. In another embodiment, a display deviceincludes the quantum dot-polymer composite or a pattern thereof. Thedisplay device may be a liquid crystal display device.

Referring to FIG. 9 and FIG. 10, in a non-limiting embodiment, theliquid crystal display includes: a liquid crystal panel 200, an opticalelement 300 (e.g., a polarizing plate) that is disposed on and/or belowthe liquid crystal panel 200, and a back light unit that is disposedbelow the lower optical element 300 and includes a blue light emittingsource. The liquid crystal panel 200 may include a lower substrate 210,an upper substrate 240, a liquid crystal layer 220 interposed betweenthe upper and the lower substrates. The device include a color filter230 disposed on a top surface or a bottom surface of the upper substrate240. The color filter includes the aforementioned quantum dot-polymercomposite or a pattern thereof.

The back light unit may include a light source 110 and optionally alight guide panel 120.

A wire plate 211 is disposed on an internal surface, e.g., a topsurface, of the lower substrate 210. The wire plate 211 may include aplurality of gate wires (not shown) and data wires (not shown), a thinfilm transistor disposed adjacent to a crossing region of gate wires anddata wires, and a pixel electrode for each pixel area, but is notlimited thereto. In an embodiment, for example, pixel areas may bedefined by the gate and data wires. The wire plate may have anystructure or feature well-known in the art, and are not particularlylimited.

The liquid crystal layer 220 may be disposed on the wire plate 211. Theliquid crystal layer 220 may include alignment layers 221 on and underthe layer 220 to initially align the liquid crystal material includedtherein. The liquid crystal material and the alignment layer may haveany structure or feature well-known in the art (e.g., liquid crystalmaterial, alignment layer material, method of forming liquid crystallayer, thickness of liquid crystal layer, or the like) and are notparticularly limited.

The optical element 300 may be a member for maintaining polarization oflight emitted from the photoluminescent color filter layer. In anembodiment, for example, the optical element 300 may be a polarizer. Ablack matrix 241 having an opening defined therethrough is disposed onthe upper substrate 240, e.g., the bottom surface of the upper substrate240, to cover a thin film transistor and a gate line, a data line, orthe like of the wire plate disposed on the lower substrate 210. Aphotoluminescent color filter layer 230 including a first color filter(R) for emitting red light, a second color filter (G) for emitting greenlight, and/or a third color filter (B) for (emitting or transmitting)blue light may be disposed on the black matrix 241 and in the opening ofthe black matrix 241. In an exemplary embodiment, the black matrix 241may have a lattice shape. A transparent common electrode 231 may bedisposed on the photoluminescent color filter layer.

A liquid crystal display (hereinafter, LCD) is a display in whichpolarized light passes through a liquid crystal and then anabsorption-type color filter to express a color. The LCD often hasdrawbacks such as a narrow viewing angle and low luminance due to a lowlevel of light transmittance of the absorption-type color filter. Forexample, in the conventional LCD including the absorption-type colorfilter, the light (e.g. the white light) provided from the back lightunit passes through the color filter to provide red, green, and bluelight, and thus the intensity of light is inevitably decreased by onethird. In contrast, in the display of the embodiments, the blue lightfrom the back light unit passes through the color filter to providelight having a desired color without the aforementioned light lossoccurring in the conventional LCD including the absorption-type colorfilter. Therefore, the display of the embodiments may show a luminanceefficiency that is at least about three times greater than that of thatconventional LCD. In addition, as the display of the embodimentsincludes the photoluminescent color filter, it may emit light atsubstantially the same intensity in all directions, allowing a widerviewing angle.

Hereinafter, the embodiments are illustrated in more detail withreference to examples. However, they are exemplary embodiments, and thepresent disclosure is not limited thereto.

EXAMPLES Example 1 [1] Preparation of Quantum Dot-Binder Dispersion

A chloroform dispersion of red or green light emitting quantum dots(InP/ZnS) including oleic acid as a hydrophobic organic ligand bonded toa surface thereof is prepared.

The chloroform dispersion including 50 grams (g) of quantum dots (red)including oleic acid as a hydrophobic organic ligand bonded to a surfacethereof is mixed with 100 g of a binder (a four membered copolymer ofmethacrylic acid, benzyl methacrylate, hydroxyethylmethacrylate, andstyrene, acid value: 130 milligrams of KOH per gram, weight averagemolecular weight: 8,000, acrylicacid:benzylmethacrylate:hydroxyethylmethacrylate:styrene (molarratio)=61.5%:12%:16.3%:10.2%) solution (polypropylene glycol monomethylether acetate having a concentration of 30 percent by weight) to providea quantum dot-binder dispersion.

A photographic image of the dispersion thus prepared is shown in FIG. 2.FIG. 2 confirms that quantum dots are uniformly dispersed in the quantumdot-binder dispersion.

[2] Preparation of the Photosensitive Composition

To the quantum dot-binder dispersion, 100 g of hexaacrylate having thefollowing structure (as a photopolymerizable monomer), 1 g of an oximeester compound (as an initiator), 30 g of TiO₂ (as a light diffusingagent), and 300 g of PGMEA (as a solvent) are added to obtain aphotosensitive composition. It is confirmed that the preparedphotosensitive composition may form dispersion without any noticeableagglomeration even after the addition of the quantum dots.

[3] Formation of Quantum Dot-Polymer Composite Pattern

The photosensitive composition obtained from item [2] is spin-coated ona glass substrate at 150 revolutions per minute (rpm) for 5 seconds (s)to provide a film. The obtained film is pre-baked at 100° C. for 2 min.The pre-baked film is irradiated with light (wavelength: 365 nanometers(nm), intensity: 100 millijoules, mJ) for 1 s under a mask having apredetermined pattern and developed by a potassium hydroxide-dilutedaqueous solution (concentration: 0.043%) for 50 s to provide a pattern.

An optical microscope image of the obtained pattern is shown in FIG. 3.

The results of FIG. 3 confirm that the composition of Example 1 may forma pattern (line width: 100 micrometers, um) including quantum dotsdispersed in a polymer. When the obtained pattern is irradiated withblue light (wavelength: 450 nm), red light or green light is emittedfrom the pattern (FIG. 4).

A transmission electron microscopic image of the obtained pattern isshown in FIG. 5. The results of FIG. 5 confirm that the quantum dots maybe uniformly dispersed in the pattern.

Comparative Example 1

100 g of the same binder solution as in Example 1, 100 g of the samephotopolymerizable monomer as in Example 1 (a hexaacrylate compound), 1g of the same photoinitiator as in Example 1, 10 g of glycoldi-3-mercaptopropionate (hereinafter, 2T), and 300 g of PGMEA are mixedto prepare a mixture.

To the obtained mixture, the same chloroform solution of the quantumdots as in Example 1 is added to prepare a photosensitive composition.

The photographic image of the obtained photosensitive composition isshown in FIG. 6. The results of FIG. 6 confirm that when the samequantum dot solution as in Example 1 is mixed with the same amount andthe same type of binder, photopolymerizable monomer, photoinitiator, andsolvent as in Example 1, the agglomeration of the quantum dots issignificant, and thus a composition including the quantum dots dispersedtherein cannot be obtained.

Comparative Example 2

A photosensitive composition is prepared to form a pattern in accordancewith the same procedure as in Example 1, except that 100 g of the bindersolution (concentration 30 wt %, polypropylene glycol monomethyl etheracetate) includes a binder resin having the same repeating units and anacid value of 30 mg KOH/g, and no reactive compound is used.

The photographic image of the prepared composition is shown in FIG. 7.

FIG. 7 confirms that the aforementioned binder solution cannot dispersethe quantum dots.

The photographic image of the prepared pattern is shown in FIG. 8. FIG.8 confirms that when the quantum dots fail to be uniformly dispersed inthe photosensitive composition, a desired pattern of the quantumdot-polymer composite cannot be obtained.

Comparative Example 3

A photosensitive composition is prepared to form a pattern in accordancewith the same procedure as in Example 1, except that 100 g of the bindersolution (concentration 30 wt %, polypropylene glycol monomethyl etheracetate) includes a binder resin having the same repeating units and anacid value of 60 mg KOH/g, and no reactive compound is used.

It is confirmed that in the prepared composition, the quantum dots arenot dispersed well and are significantly agglomerated, and by using theprepared composition, a desired pattern of the quantum dot polymercomposite cannot be obtained.

While this disclosure has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A photosensitive composition comprising: aquantum dot dispersion; a photopolymerizable monomer comprising acarbon-carbon double bond; and a photoinitiator, wherein the quantum dotdispersion comprises an acid group-containing polymer and a plurality ofquantum dots dispersed in the acid group-containing polymer, and theacid group-containing polymer has an acid value of greater than or equalto about 100 milligrams of KOH per gram of acid group-containing polymeras measured by a titration with a solution of potassium hydroxide,wherein the quantum dots comprise an organic ligand bound to a surfacethereof, and wherein the organic ligand comprises RCOOH, RNH₂, R₂NH,R₃N, RSH, R₃P, ROH, RCOOR′, RPO(OH)₂, R₂POOH (wherein R and R′ areindependently a C5 to C24 aliphatic hydrocarbon group, a C5 to C20alicyclic hydrocarbon group, or a C6 to C20 aromatic hydrocarbon group),or a combination thereof, wherein the acid group-containing polymer is acopolymer consisting of a first repeating unit, a second repeating unit,and a third repeating unit, wherein the first repeating unit is arepeating unit represented by Chemical Formula 1-1, a repeating unitrepresented by Chemical Formula 1-2, or a combination thereof:

wherein R¹ is hydrogen, a C1 to C3 alkyl group, or —(CH₂)_(n1)—COOH(wherein n1 is 0 to 2), R² is hydrogen, a C1 to C3 alkyl group, or—COOH, L is a single bond, a C1 to C15 aliphatic hydrocarbon group, a C6to C30 aromatic hydrocarbon group, a C6 to C30 alicyclic hydrocarbongroup, or a C1 to C15 aliphatic hydrocarbon group substituted with a C6to C30 aromatic hydrocarbon group or a C6 to C30 alicyclic hydrocarbongroup, and * indicates a portion connected to an adjacent atom;

wherein R¹ is hydrogen, a C1 to C3 alkyl group, or —(CH₂)_(n1)—COOH(wherein n1 is 0 to 2), R² is hydrogen or a C1 to C3 alkyl group, L is aC1 to C15 alkylene group, a C1 to C15 alkylene group wherein at leastone methylene group is substituted with —C(═O)—, —O—, or —C(═O)O—, a C6to C30 aromatic hydrocarbon group, a C6 to C30 alicyclic hydrocarbongroup, or a C1 to C15 aliphatic hydrocarbon group substituted with a C6to C30 aromatic hydrocarbon group or a C6 to C30 alicyclic hydrocarbongroup, n is an integer of 1 to 3, and * indicates a portion connected toan adjacent atom; wherein the second repeating unit is a repeating unitrepresented by Chemical Formula 2, a repeating unit represented byChemical Formula 4, a repeating unit represented by Chemical Formula 5,a repeating unit represented by Chemical Formula A, or a combinationthereof:

wherein R¹ is hydrogen or a C1 to C3 alkyl group, R² is a C1 to C15aliphatic hydrocarbon group, a C6 to C30 aromatic hydrocarbon group, aC6 to C30 alicyclic hydrocarbon group, or a C1 to C15 aliphatichydrocarbon group substituted with a C6 to C30 aromatic hydrocarbongroup or a C6 to C30 alicyclic hydrocarbon group, R³ is hydrogen or a C1to C3 alkyl group, and * indicates a portion connected to an adjacentatom;

wherein R¹ is hydrogen or a C1 to C3 alkyl group, L is a C1 to C15alkylene group, a C1 to C15 alkylene group wherein at least onemethylene group is substituted with —C(═O)—, —O—, or —C(═O)O—, a C6 toC30 aromatic hydrocarbon group, a C6 to C30 alicyclic hydrocarbon group,or a C1 to C15 aliphatic hydrocarbon group substituted with a C6 to C30aromatic hydrocarbon group or a C6 to C30 alicyclic hydrocarbon group,R² is a C1 to C15 aliphatic hydrocarbon group, a C6 to C30 aromatichydrocarbon group, a C6 to C30 alicyclic hydrocarbon group, or a C1 toC15 aliphatic hydrocarbon group substituted with a C6 to C30 aromatichydrocarbon group or a C6 to C30 alicyclic hydrocarbon group, R³ ishydrogen or a C1 to C3 alkyl group, n is an integer of 1 to 3, and *indicates a portion connected to an adjacent atom;

wherein each of R¹ and R² is independently hydrogen or a C1 to C3 alkylgroup, Ar is a substituted or unsubstituted C6 to C30 aromatichydrocarbon group or a substituted or unsubstituted C6 to C30 alicyclichydrocarbon group, and * indicates a portion connected to an adjacentatom;

wherein R¹ is hydrogen or a C1 to C3 alkyl group, R² is a C1 to C15aliphatic hydrocarbon group, a C6 to C30 aromatic hydrocarbon group, aC6 to C30 alicyclic hydrocarbon group, or a C1 to C15 aliphatichydrocarbon group substituted with a C6 to C30 aromatic hydrocarbongroup or a C6 to C30 alicyclic hydrocarbon group, R³ is hydrogen or a C1to C3 alkyl group, and * indicates a portion connected to an adjacentatom, wherein the third repeating unit is a repeating unit representedby Chemical Formula 3:

wherein each of R¹ and R² is independently hydrogen or a C1 to C3 alkylgroup, L is a C1 to C15 alkylene group, a C1 to C15 alkylene groupwherein at least one methylene group is substituted with —C(═O)—, —O—,or —C(═O)O—, a C6 to C30 aromatic hydrocarbon group, a C6 to C30alicyclic hydrocarbon group, or a C1 to C15 aliphatic hydrocarbon groupsubstituted with a C6 to C30 aromatic hydrocarbon group or a C6 to C30alicyclic hydrocarbon group, Z is a hydroxyl group (—OH), a mercaptogroup (—SH), or an amino group (—NHR, wherein R is hydrogen or a C1 toC5 alkyl group), and * indicates a portion connected to an adjacentatom, wherein the photosensitive composition is in a form of a colloidaldispersion having a dispersed phase with a dimension of greater than orequal to about 1 nanometer and less than or equal to about 1 micrometer,wherein in the photosensitive composition, the plurality of quantum dotsare configured to have a quantum yield of greater than or equal to about60% as measured with irradiation of an excitation light, wherein anamount of the quantum dot comprising the organic ligand is greater thanabout 5 weight percent based on a total amount of the composition. 2.The photosensitive composition of claim 1, wherein the organic liganddoes not comprise a photopolymerizable functional group.
 3. Thephotosensitive composition of claim 2, wherein the organic ligandfurther comprises a polymeric organic ligand.
 4. The photosensitivecomposition of claim 1, wherein the acid group-containing polymer has anacid value of greater than or equal to about 120 milligrams of KOH pergram and less than or equal to about 200 milligrams of KOH per gram. 5.The photosensitive composition of claim 1, wherein the quantum dotcomprises a Group II-VI compound, a Group III-V compound, a Group IV-VIcompound, a Group IV element or compound, a Group compound, a GroupI—II-IV-IV compound, or a combination thereof.
 6. The photosensitivecomposition of claim 1, wherein the organic ligand comprises RCOOH,wherein R is a C5 to C24 aliphatic hydrocarbon group, and wherein aweight average molecular weight of the acid group-containing polymer isless than or equal to about 50,000 grams per mole.
 7. The photosensitivecomposition of claim 1, wherein the amount of the first repeating unitis greater than 20 mole percent and less than or equal to about 95 molepercent in the acid group-containing polymer.
 8. The photosensitivecomposition of claim 1, wherein the acid group-containing polymercomprises a copolymer of a first monomer selected from (meth)acrylicacid and the second and third monomers selected fromalkyl(meth)acrylate, arylalkyl(meth)acrylate,hydroxyalkyl(meth)acrylate, and styrene.
 9. The photosensitivecomposition of claim 1, wherein the acid group-containing polymer has anacid value of between about 125 milligrams of KOH per gram and about 200milligrams of KOH per gram.
 10. The photosensitive composition of claim1, wherein a weight average molecular weight of the acidgroup-containing polymer is greater than or equal to about 1,000 gramsper mole and less than or equal to about 100,000 grams per mole.
 11. Thephotosensitive composition of claim 1, wherein the photosensitivecomposition further comprises a solvent, and wherein based on a totalamount of the composition, the photosensitive composition comprises:about 5 percent by weight to about 40 percent by weight of the quantumdots; about 0.5 percent by weight to about 35 percent by weight of theacid group-containing polymer; about 0.5 percent by weight to about 30percent by weight of the photopolymerizable monomer; about 0.1 percentby weight to about 10 percent by weight of the photoinitiator; and abalance amount of the solvent.
 12. A method of producing aphotosensitive composition of claim 1, wherein the method comprises:dissolving the acid group-containing polymer in the solvent to prepare apolymer solution; combining the plurality of quantum dots having theorganic ligand bonded to a surface thereof with the polymer solution toobtain the quantum dot dispersion; and combining the quantum dotdispersion with the photopolymerizable monomer comprising acarbon-carbon double bond, the photoinitiator, and optionally a solvent.13. The method of claim 12, wherein the acid value of the acidgroup-containing polymer is greater than or equal to about 90 milligramsof KOH per gram and less than about 200 milligrams of KOH per gram. 14.The method of claim 12, wherein the amount of the quantum dot comprisingthe organic ligand is greater than or equal to about 10 wt % based on atotal amount of the composition.
 15. The photosensitive composition ofclaim 1, wherein the amount of the quantum dot comprising the organicligand is greater than or equal to about 10 wt % based on a total amountof the composition.
 16. The photosensitive composition of claim 1,wherein the acid value of the acid group-containing polymer is greaterthan or equal to about 110 milligrams of KOH per gram and less thanabout 180 milligrams of KOH per gram and a molecular weight of the acidgroup-containing polymer is less than or equal to about 50,000 g/mol.17. The photosensitive composition of claim 1, the photosensitivecomposition further comprises a light diffusing agent and the lightdiffusing agent comprises an inorganic oxide particle selected from anyof alumina, silica, zirconia, titanium oxide particulates, zinc oxide,or a combination thereof, a metal particle, or a combination thereof.18. The photosensitive composition of claim 1, wherein the acid value ofthe acid group-containing polymer is greater than or equal to about 90milligrams of KOH per gram and less than about 200 milligrams of KOH pergram.